Manna Hill Project Exploration Update
Cobra Resources plc has commenced drilling at its Manna Hill project, focusing on the Blue Rose prospect where previous drilling intersected skarn-hosted copper-gold mineralization across 1.6km of strike, with the last hole yielding 48m at 2.3% Cu and 0.79 g/t Au from 11m. The initial stage involves up to 15 drillholes for approximately 3,000m, testing depth and strike continuity of existing mineralization, as well as exploring the Neptune Rose and Black Baccara targets. Stage 1 drilling is expected to conclude within two weeks, with assay results anticipated in March, and further drilling will be determined by geological observations.
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Cobra (LSE: COBR), a South Australian mineral exploration and development company, is pleased to announce drilling has commenced at the Manna Hill project.
Cobra has a 12-month option to acquire the Manna Hill Project and will focus initially on the Blue Rose priority prospect ("Blue Rose") where existing drilling has intersected skarn hosted copper-gold mineralisation across 1.6km of strike immediately adjacent to a geophysical anomaly interpretated as a porphyry intrusion1.
To watch a video of Rupert Verco, Managing Director discussing the drilling from site follow the link: https://investors.cobraplc.com/link/rLwVRe
Highlights:
- Approvals in place to drill up to 50 drillholes where Stage 1 drilling (currently underway) will comprise up to 15 drillholes for approximately 3,000m where:
o Nine drillholes designed to test depth and strike continuity of existing Blue Rose Skarn mineralisation where the last hole drilled intersected 48m @ 2.3% Cu and 0.79 g/t Au from 11m.
o Four drillholes testing Neptune Rose Skarn - A ~1.2km chargeability anomaly interpreted to be a second fold limb of the Saddleworth formation, the limestone unit that hosts Blue Rose mineralisation.
o Two holes testing the Black Baccara target particularly:
§ The porphyry envelope, defined by a resistive and highly chargeable anomaly that envelopes the remnant magnetised intrusion.
§ A conductive and chargeable pipe structure, interpreted as a conjugate fault that intersects the skarn unit.
- Stage 1 drilling expected to take two weeks with final assays expected in March.
- Further drilling to be determined from the geological observations made in Stage 1
Rupert Verco, Managing Director of Cobra, commented:
"This is a significant opportunity for Cobra and its shareholders; we have the perfect balance between adding scale within previously defined high-grade mineralisation at Blue Rose and significant discovery upside at Neptune Rose and Black Baccara Targets.
This programme is targeting a scalable copper discovery in the right market and the right jurisdiction. At the end of this programme, we are hopeful that the company will be advancing two significant projects."
The Blue Rose Prospect is of skarn-replacement type where previous exploration has defined copper-gold-molybdenum across 1.6 km of continuous strike where drilling has defined the previous intersections:
o [RABR822] 47m at 2.2% Cu and 0.76 g.t Au from 11m
o [RCBR025] 132m at 0.52% Cu from 8m including 48m at 1.04% Cu
o [RABR152] 41m at 1.6% Cu from 9m including 18m at 2.03% Cu
o [RABR205] 43m at 0.6% Cu from 12m
o [RCBR030] 52m at 0.77% Cu and 0.94 g/t Au from 80m
o [RABR198] 24m at 1.0% Cu from 18m incl. 3m @ 1.23g/t Au
o [RCBR021] 23m at 1.4% Cu from 73m incl. 12m @ 0.71g/t Au
o [RABR205] 43m at 0.6% Cu from 12m
Geophysics including gravity, induced polarisation and magnetics have been used in collaboration with geochemistry to refine the interpretation of both the stratigraphic unit hosting shallow skarn mineralisation, and porphyry mineralisation that in interpreted to envelope a remnant magnetised intrusion. Two additional target zones have been strongly supported by the results of a recent IP survey have been incorporated into stage 1 of the current drilling programme and are highlighted in Figure 1.
Figure 1: Commencement of drilling at Blue Rose
Figure 2. Blue Rose, Neptune Rose and Black Baccara targets with planned drillhole collars
Figure 3: 3D image highlighting IP chargeability sections with designed drillhole traces
Figure 4: Cross section of section 428430mE highlighting designed drill traces (stage 1 in black, stage 2 in orange) targeting a broad chargeability anomaly
About the Manna Hill Project
The project sits along the national railway and Barrier Highway between the mining hub of Broken Hill, the port and base metals smelter and Port Pirie and the City of Adelaide.
- Cobra RNS: Option to Acquire Significant Copper Project, 26 August 2025
References:
- Cobra RNS: Option to Acquire Significant Copper Project, 26 August 2025
Regional map showing Cobra's tenements in South Australia
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Appendix 2: JORC Code, 2012 Edition - Table 3
| Criteria | JORC Code explanation | Commentary |
| Sampling techniques | · Nature and quality of sampling (eg cut channels, random chips, or specific specialised industry standard measurement tools appropriate to the minerals under investigation, such as down hole gamma sondes, or handheld XRF instruments, etc). These examples should not be taken as limiting the broad meaning of sampling. · Include reference to measures taken to ensure sample representivity and the appropriate calibration of any measurement tools or systems used. · Aspects of the determination of mineralisation that are Material to the Public Report. · In cases where 'industry standard' work has been done this would be relatively simple (eg 'reverse circulation drilling was used to obtain 1 m samples from which 3 kg was pulverised to produce a 30 g charge for fire assay'). In other cases more explanation may be required, such as where there is coarse gold that has inherent sampling problems. Unusual commodities or mineralisation types (eg submarine nodules) may warrant disclosure of detailed information. | Historic · Historic drill programs have been conducted by multiple companies and methods the historically reported results are being reviewed prior to any broader reporting of results. In general lab assay results across differing programs show comparable tenors of grade and distribution. |
| Drilling techniques | · Drill type (eg core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or standard tube, depth of diamond tails, face-sampling bit or other type, whether core is oriented and if so, by what method, etc). | Historic Drilling · Historic drill methods were predominantly aircore and RC driiling with some diamond drilling reported |
| Drill sample recovery | · Method of recording and assessing core and chip sample recoveries and results assessed. · Measures taken to maximise sample recovery and ensure representative nature of the samples. · Whether a relationship exists between sample recovery and grade and whether sample bias may have occurred due to preferential loss/gain of fine/coarse material. | · Historic recoveries have not been assessed. · Drill methods and geological conditions are not expected to promote significant reduced recovery or sample biasing |
| Logging | · Whether core and chip samples have been geologically and geotechnically logged to a level of detail to support appropriate Mineral Resource estimation, mining studies and metallurgical studies. · Whether logging is qualitative or quantitative in nature. Core (or costean, channel, etc) photography. · The total length and percentage of the relevant intersections logged. | · Historic logging has been completed with a number of different geological logging codes. These are being translated into a standardized logging format prior to entry into the Cobra Drillhole Database |
| Sub-sampling techniques and sample preparation | · If core, whether cut or sawn and whether quarter, half or all core taken. · If non-core, whether riffled, tube sampled, rotary split, etc and whether sampled wet or dry. · For all sample types, the nature, quality and appropriateness of the sample preparation technique. · Quality control procedures adopted for all sub-sampling stages to maximise representivity of samples. · Measures taken to ensure that the sampling is representative of the in situ material collected, including for instance results for field duplicate/second-half sampling. · Whether sample sizes are appropriate to the grain size of the material being sampled. | Historic · Historic sampling has not been assessed. |
| Quality of assay data and laboratory tests | · The nature, quality and appropriateness of the assaying and laboratory procedures used and whether the technique is considered partial or total. · For geophysical tools, spectrometers, handheld XRF instruments, etc, the parameters used in determining the analysis including instrument make and model, reading times, calibrations factors applied and their derivation, etc. · Nature of quality control procedures adopted (eg standards, blanks, duplicates, external laboratory checks) and whether acceptable levels of accuracy (ie lack of bias) and precision have been established. | Historic · Lab certificates for a large number of drill samples have been retained from historic drilling. These certificates will be used for the import of data into Cobra's drillhole database. |
| Verification of sampling and assaying | · The verification of significant intersections by either independent or alternative company personnel. · The use of twinned holes. · Documentation of primary data, data entry procedures, data verification, data storage (physical and electronic) protocols. · Discuss any adjustment to assay data. | Historic · Reported significant intercepts have been reported to the Australian Stock Exchange in the past · Primary assay data and drill logs for reported holes have been reviewed by Cobra staff · Further migration of historic data into the Cobra drillhole database is underway with validation during this process to be undertaken. |
| Location of data points | · Accuracy and quality of surveys used to locate drill holes (collar and down-hole surveys), trenches, mine workings and other locations used in Mineral Resource estimation. · Specification of the grid system used. · Quality and adequacy of topographic control. | Historic · Historic Drillholes were recorded with a number of different datums. · Validation of the datums used for each program have been conducted and are continuing.The key historic drilling used for planning of the January 2026 drill program have high confidence in the datum used and have been assessed in the field |
| Data spacing and distribution | · Data spacing for reporting of Exploration Results. · Whether the data spacing and distribution is sufficient to establish the degree of geological and grade continuity appropriate for the Mineral Resource and Ore Reserve estimation procedure(s) and classifications applied. · Whether sample compositing has been applied. | Historic · Historic drilling was variably spaced. The drill spacing was sufficient to define mineralization trends at the Blue Rose Skarn but not to the extent of defining a resource. · Drilling at Desert Rose and Double Delight has not been sufficient to assess the prospects and has been sparse |
| Orientation of data in relation to geological structure | · Whether the orientation of sampling achieves unbiased sampling of possible structures and the extent to which this is known, considering the deposit type. · If the relationship between the drilling orientation and the orientation of key mineralised structures is considered to have introduced a sampling bias, this should be assessed and reported if material. | · Drillholes have been vertical or south dipping · Deeper historic drilling has been south dipping · Mineralization is interpreted to be steeply dipping with limited success to date in identifying a slight north or south dip. · Deeper planned drilling is expected to help with this interpretation |
| Audits or reviews | · The results of any audits or reviews of sampling techniques and data. | · |
| Appendix 3: Section 2 reporting of exploration results | ||
| Criteria | JORC Code explanation | Commentary |
| Mineral tenement and land tenure status | · Type, reference name/number, location and ownership including agreements or material issues with third parties such as joint ventures, partnerships, overriding royalties, native title interests, historical sites, wilderness or national park and environmental settings. · The security of the tenure held at the time of reporting along with any known impediments to obtaining a licence to operate in the area. | · Blue Rose is located on EL6009 that is held by Hamelin Gully Pty Ltd. Manna Hill Mining Pty Ltd, a subsidiary of Cobra Resources Plc has a 12-month option to acquire Hamelin Gully. · This drilling forms part of the company's strategy to seek shareholder approval to exercise the option. · A 1% Over Riding Royalty Agreement is registered between Hamelin Gully and Springton Trust A Native Title Agreement is in place between the Wilyakali People and Hamelin Gully Pty Ltd Cultural heritage surveys have been completed over EL6009, clearing proposed drill sites |
| Geology | · Deposit type, geological setting and style of mineralisation. | Blue Rose · Blue Rose is skarn hosted mineralization on the margins of the Anabama Granite · The skarn is interpreted to be stratabound Neptune Rose · Is interpreted to be hosted within skarn mineralization. · Assessment of the structural vs stratigraphic controls on mineralization will be assessed during drilling Black Baccara · Is interpret to be a sulphide rich halo around a magnetic low core. Assessment of Geological survey spectral from nearby "near miss" diamond holes indicate the metamorphic gradient and spectral responses anticipated from a porphyry system |
| Further work | · The nature and scale of planned further work (eg tests for lateral extensions or depth extensions or large-scale step-out drilling). · Diagrams clearly highlighting the areas of possible extensions, including the main geological interpretations and future drilling areas, provided this information is not commercially sensitive. | · RC drill program at Blue Rose, Desert Rose and Double Delight in early January 2026 · Follow up diamond drilling at Desert Rose · Greenfields soil sampling program |
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